Colbalt Calibur 3: Open-source Canvas+Node MMO
Colbalt Calibur 3 is an real-time-ish multi-player MMO written by Thomas Hunter that uses Canvas and Node.js. It’s open source duel licensed under the BSD/GPL and is the start of a multi-player minecrafty resource mining and building type of world.
The code is up on GitHub, and there are instructions for setting up a free-server, and a sample world at http://zyu.me/